CVE-2026-43484 Details
Description
In the Linux kernel, the following vulnerability has been resolved: mmc: core: Avoid bitfield RMW for claim/retune flags Move claimed and retune control flags out of the bitfield word to avoid unrelated RMW side effects in asynchronous contexts. The host->claimed bit shared a word with retune flags. Writes to claimed in __mmc_claim_host() or retune_now in mmc_mq_queue_rq() can overwrite other bits when concurrent updates happen in other contexts, triggering spurious WARN_ON(!host->claimed). Convert claimed, can_retune, retune_now and retune_paused to bool to remove shared-word coupling.
A vulnerability in the Linux kernel's MMC (MultiMediaCard) core has been addressed. The issue involved the management of claim and retune control flags, which were improperly handled as bitfields. This configuration led to unintended read-modify-write (RMW) side effects in asynchronous contexts. Specifically, the 'claimed' bit shared a word with retune flags, allowing writes to one to inadvertently overwrite the other. This could trigger false warnings about the host being unclaimed. The vulnerability affected the Linux kernel stable tree.
The vulnerability has been fixed by moving the claimed and retune flags out of the bitfield and into separate boolean variables. This change eliminates the shared-word coupling that caused the issue, allowing for safe concurrent updates. Users should upgrade to the latest version of the Linux kernel stable tree where this fix has been applied.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/0e06cc511c61cff1591e5435a207759adcc76b6d | kernel.org | Patch |
| https://git.kernel.org/stable/c/270277c2ab631044867adb1bd2f2433d3892de6e | kernel.org | Patch |
| https://git.kernel.org/stable/c/41dce4dae583a8ce06a7ebf4ce704c46a142957c | kernel.org | Patch |
| https://git.kernel.org/stable/c/45038e03f15e992c48603fff8c6b1c9be5397ac9 | kernel.org | Patch |
| https://git.kernel.org/stable/c/901084c51a0a8fb42a3f37d2e9c62083c495f824 | kernel.org | Patch |
| https://git.kernel.org/stable/c/bb7fc2498c3bb25fa6a91f22f4760005325cfbd5 | kernel.org | Patch |
| https://git.kernel.org/stable/c/d3a3caf44c8ec26f5d63dc17c1c7242effa60ebc | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 4.15, < 5.15.203 >= 5.16, < 6.1.167 >= 6.2, < 6.6.130 >= 6.7, < 6.12.78 >= 6.13, < 6.18.19 >= 6.19, < 6.19.9 7.0 rc1 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 26, 2026 | Initial Analysis | [email protected] |
| Jun 17, 2026 | CVE Modified | kernel.org |
| May 13, 2026 | New CVE Received | kernel.org |